This invention relates to mechanism for testing fire suppression systems in military tanks. Such systems are used to prevent explosive type fires within the tank, incident to passage of an enemy projectile into or through the tank hull.
In order to accomplish its function the suppression system must be quick-acting; normally the system must achieve a fire-out condition within about 0.2 second after the initial optical flash signal generated by passage of the enemy shell into the hull.
One exemplary fire suppression system comprises a plural number of optical fire sensors positioned in the engine compartment to generate an electrical signal within a few milliseconds after a fire condition is sensed in the compartment. The signal is amplified and applied as a step voltage output to quick-acting valves on one or more storage bottles containing pressurized liquid fire suppressant. One liquid commonly used is C Br F3, tradename Halon 1301.
The storage bottles have fluid connections with fire suppressant spray tubes extending within the engine compartment. Sprayed liquid extinguishes the fire before it can explosively propogate into an unmanageable fireball.
Fire suppression systems of the above-referenced type may be tested by firing HEAT (High Explosive Antitank) rounds into tanks equipped with the systems. Such tests are performed for various reasons, e.g. to test the reliability of the components (sensors, amplifiers, valves and spray tubes), to test the effect of location changes for components (e.g. sensors, and spray tubes), or to test new supplier equipment (qualification tests).
The principal sources for explosive type fires are the fuel tanks; passage of a heat round through a fuel tank will usually generate an explosive-type fire. The fuel tanks are located within the engine compartment, such that the optical sensors must be able to optically view various zones between the engine surfaces and the fuel tank surfaces. Projecting surfaces on the engine components (e.g. turbocharger, generator, starter, oil coolers, etc.) can interrupt or interfere with the optical signal. In order for the tests to be realistic such tests have to be carried out with the engine installed in the compartment. Tests performed in an empty engine compartment are not realistic or definitive.
Unfortunately tank engines are relatively costly hardware items. Preferably engines used in such tests are "scrap" or old engines having only marginal value for combat purposes. Also, the test engines are preferably cannabilized of operating internal parts, e.g. pistons, injectors, crankshafts, etc., since the components can be destructed during the test period.
In one typical tank power plant the engine is an air-cooled engine wherein the coolant air fans are driven from the engine through gearing contained within the transmission. Such fans produce a significant flow of air through the engine compartment during normal operations (i.e. in combat situations). Fire suppression system testing is preferably carried out with the fans running; the significant air flow through the compartment can affect the progress of the exploding fireball, as well as the direction and spray pattern of the liquid (vapor) fire suppressant. If the fans are not running the tests may not be conclusive or fully informative on the merits of the tested equipment.
The present invention relates to an add-on mechanism for facilitating the realistic testing of fire suppression systems without requiring the engine to be running during the test period. The add-on mechanism comprises an auxiliary (external) power source connected to the transmission to drive the air coolant fans even though the engine is inoperable or inactive. The principal object of the invention is to permit the testing operations to be carried out with scrap or cannabilized engines having minimal value for combat purposes.